Climbing aid

ABSTRACT

A climbing aid in the form of a camming device comprising two support arms rotatably mounted about an axis, each arm having at its free end at least two pivotally mounted cams, and locking means for preventing rotation of the arms on reaching a predetermined angle with respect to each other.

The present invention relates to a climbing aid, particularly but not exclusively a spring loaded camming device for rock climbing.

Spring loaded camming devices (SLCDs or cams) were invented by Ray Jardine in the late 1970s to provide a safety protection device for rock climbing (U.S. Pat. No. 4,184,657). The device enables an rope to be anchored within a narrow gap or crevasse in a rockface and has the advantage of causing no damage to the rock face in contrast to earlier types of anchoring device that were physically jammed into the rock surface causing scarring of the face on their removal.

The camming device comprises two to four cams mounted on an axle such that pulling on the axle forces the cams to spread apart. The cams are pivotally mounted on a spindle carried by a support bar and are adapted to engage opposing walls of a crack in a rockface, the cams being biased towards the open position. A trigger linked to the cams via cabling is provided to enable the cams to be pulled into the closed position to allow insertion into a crack or pocket in a rock. Once inserted, release of the trigger causes the cams to expand and hold on to the rockface. Pulling further on the support bar increases the counter-pressure of the cams on the rockface, thereby strengthening the grip of the SLCD. Removal of the SLCD is achieved by pulling the trigger to rotate the cams to their closed position. A climbing rope can be attached to a sling and carabiner at the end of the support bar.

Whilst the aforementioned cam is extremely popular and entirely fit for purpose, its use is limited to cracks or holes in rocks or other climbing structures that are of a small dimension (generally less than 100 mm, more often less than 50 mm).

It is an object of the present invention to provide an improved climbing aid, in particular a spring loaded camming device, that aims to overcome or at least alleviate the abovementioned drawbacks.

Accordingly, the present invention provides a climbing aid comprising two support arms rotatably mounted about an axis, each arm having at its free end at least one pivotally mounted cam, and locking means for preventing rotation of the arms on reaching a predetermined angle with respect to each other.

Ideally, each arm carries two cams more preferably two parallel cams. The cams should be spring mounted and lie in the same plane as the arms.

Preferably, the arms are locked in position when the intended lower faces of the arms are at an angle of approximately 180 degrees, more preferably exactly 180 degrees. The arms are preferably the same length, being mounted about a central axis. It is envisaged that the maximum length of the climbing aid, i.e. when the arms are in the locked position, will be at least 100 mm, more preferably at least 150 mm. It is to be appreciated that camming devices of different sizes may be provided according to the present invention.

It is preferable for the intended upper faces of the arms to be angled such that, in the locked position, the upper faces lie parallel with the bracing angle of the cams. This angle will depend upon the type of cam to be used, with the angle being set to the definitive bracing angle of the cams. For example, if a proprietary cam of Wild Country (Trade Mark) is used, the angle should be 13.75 degrees.

In a preferred embodiment of the present invention, each arm comprises a limb having a cylindrical spindle extending transversely thereto at one end and a circular disc extending transversely thereto at the other end. Preferably, the arm is formed as an integral unit. A cam may be spring mounted at each end of the spindle by suitable means.

The disc is preferably approximately half the breadth of the limb of the arm and provided with a groove in the intended upper region thereof. More preferably, the discs of the two arms are located on opposing sides of their respective limbs to enable the discs to abut together in the assembled device. Each disc is preferably provided with a bore through the centre thereof for receiving an axle.

Preferably, locking of the arms is achieved automatically upon reaching the predetermined angle. For example, in one embodiment the locking means is such that it can locate in the grooves of the discs when they become aligned thereby preventing further rotation of the arms with respect to each other. More preferably, the locking means comprises a stop member that is slidably mounted with respect to the discs of the arms. In a preferred embodiment, the stop member is slidably located within a housing that bridges the arms of the device.

More preferably, the housing is in the general shape of a letter “n” having two legs that lie parallel to the face of the discs and a crosspiece that lies above the top of the discs, each leg having a longitudinal slot for passage of the stop member. The stop member is provided with means for its operation, such as a strap or cable. More preferably still, the stop member is biased towards its lowered or locked position, for example by means of a spring, with the strap or cable being required to pull the member upwardly out of the grooves. The axle upon which the arms are mounted preferably extends between the legs of the housing, being secured thereto by suitable means. A further crosspiece may be provided for attachment of cabling, preferably being situated towards the free ends of the legs of the housing.

It is preferable to provide means for affecting rotation of the cams. More preferably a cable or strapping is attached to each cam to allow manual rotation of the cams. Preferably, the cable is attached to the limb of its respective arm at a point along its length. It is preferable to provide a finger loop in the end of each cable.

The profile of the periphery of the cams may be chosen depending upon the type of surface between which they are to be mounted. For example, cams having a ribbed surface may be used for rock climbing purposes but spices may be provided if the device is to be used for glacier climbing. In the latter case, it is preferable to provide a cover for the spikes, such as a rubber cap.

The climbing aid according to the present invention may be constructed of any suitable materials that provide the requisite strength but with consideration to weight limitations. It is envisaged that steel or other alloys would be used in its construction. Most preferably, the arms are constructed from Aerospace Grade 7075 stem alloy. Preferably, components of the device, such as the arms and cams, are provided with weight-saving holes tberethrough at appropriate locations.

For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made by way of example only to the accompanying drawings in which:

FIG. 1 is schematic diagram of a camming device according to one embodiment of the present invention, shown located between two rock faces;

FIG. 2 is a perspective view of the camming device shown in FIG. 1, shown fully extended:

FIG. 3 is an exploded view of the camming device shown in FIGS. 1 and 2;

FIG. 4 is a perspective view of an arm for a camming device according to one embodiment of the present invention;

FIG. 5 is a plan view of the arm shown in FIG. 4;

FIG. 6 is an exploded partial view of the camming device of FIGS. 1 and 2, showing the mechanism for attachment of the cams to one arm;

FIG. 7 is a view of a camming device according to the present invention, shown from above located between two rock faces;

FIGS. 8 a and 8 b are respectively a perspective and plan view of the central housing for a camming device according to an embodiment of the present invention;

FIGS. 9 a and 9 b illustrate operation of the cams of the camming device according to the present invention;

FIGS. 10 a to 10 d illustrate the steps of installation and removal of a camming device according to the present invention;

FIG. 11 is a schematic diagram of a camming device according to another embodiment of the present invention, shown located between two ice structures; and

FIG. 12 is a perspective view of a cam of the camming device shown in FIG. 11.

Referring to FIGS. 1 to 10 b of the accompanying drawings, a spring loaded camming device (SLCD) according to one embodiment of the present invention is illustrated. Briefly, the device comprises two arms 2, 4 pivotally mounted on a central axle 6, each arm having at its free end a pair of spring-mounted cams 8 carried on a spindle 10. The central axle is located within a housing 12 that has means to lock the arms in an extended, open position. Thus the arms can be moved between a closed position to enable insertion of the device between two faces of a climbing structure, such as a rockface, and an extended, locked position, wherein the arms are at an angle of approximately 90 degrees to the central axle (i.e. 180 degrees to each other). In this position, the cams are forced against the rock surface and serve to grip the device therebetween. Any downward pressure on the central axle will be transferred to the cams causing them to pivot and grip the rock face further. The provision of the arms enables the device to be secured between gaps in excess of 100 mm wide to enable climbers to make use of such crevasses for anchorage purposes.

The structure of the aforementioned camming device will now be described in further detail. Referring in particular to FIGS. 4 to 6 of the accompanying drawings, the preferred construction for an arm of the camming device is illustrated. Each arm 2, 4 has a main limb 20 provided with a circular member at each end, extending transversely thereto. One circular member comprises a cylindrical spindle-forming member 22 extending beyond the edges of the limb whilst the other is in the form of a disc 24 of larger diameter than the member 22 but approximately half the breadth of the limb. Each end of the spindle-forming member is provided with a central bore 26 and receives a cam 8, the cam being pivotally mounted with respect of the spindle by means of an end axle 28 comprising a male and female thread which extends through a hole provided in each cam and the bore of the spindle. Springs 30 are provided between the inner face of each cam and the respective end of the spindle, opposing ends of each spring being located in recesses or holes 31 provided in the spindle and cam. The springs positioned at either end of the spindle are coiled in opposite directions (mirror image of forces for opposite spring), as shown in FIG. 6. The disc 24 located at the other end of the limb has a central bore 32 and a groove or slot 34 in the intended upper part of the disc (see FIGS. 4 and 5).

Two arms are connected together by aligning the discs 24. In this respect, it is to be appreciated that the limbs of the arms 2, 4 extend in opposite directions and the discs 24 are mounted at opposing sides of their respective limb to enable them to abut one another in the assembled device (see, for example, FIG. 2). The discs are pivotally mounted with respect to each other by means of the central axle 6 extending through the bore 32 of each disc. The upper face of each arm is angled such that when the intended lower faces of the arms lie at 180 degrees to each other, the angle of each upper arm lies parallel with the definitive bracing angle of the cam attached to the end of the arm (dependent upon the particular type of cam used).

Referring in particular to FIGS. 8 a and 8 b, the housing 12 is in the general shape of the letter “n”, having two substantially parallel legs 40 connected a crosspiece 42. Each leg of the housing is provided with two holes 44, 46 towards the free end thereof the corresponding holes in the other leg being in alignment therewith. Additionally, the upper portion of each leg is provided with a longitudinal slot 48 for receiving a stop member in the form of bar 50. A spring 52 is provided to biase the stop member towards the lower position and a split pin 54 is provided through one end of the member to minimise sideways movement. A cable 56 with loop extends upwardly from the stop member.

The housing 12 is mounted over aligned discs of the arms and the central axle extends through the upper holes 44 of the housing and through the bores of the discs (see FIGS. 1 to 3). A farther rod 60 extends through the lower holes 46 of the housing for attachment of a cable assembly 62. This can be linked to a sling 64 and karabiner 66 for attachment of a climbing rope 68.

In this manner the opposing arms 2, 4 of the camming device are pivotally mounted with respect to each other until their respective groove/slots 34 become aligned with each other. Alignment enables the biased stop member 50 to slide down the longitudinal slot 48 to rest in the aligned grooves 34 thereby locking the arms in their extended position.

Additionally, the cams 8 located at the end of each arm are provided with cable or strapping 70 to allow manual rotation of each cam about the spindle. The cable 70 is attached at one point 72 to the base of the limb of the arm 8 and provided with finger loops 74, as illustrated in FIGS. 9 a and 9 b. The attachment point 72 enables the cams to be set at an optimum angle when not in use and allows the finger loops to be readily accessible to the user.

The device is constructed of appropriate materials, such as steel or other alloys to provide the necessary strength but with awareness to weight limitations. The preferred material for the arms and cams is Aerospace Grade 7075 stem alloy. Weight-saving holes 90 are provided throughout device, for example in the cams and limbs of arms.

FIGS. 10 a to 10 d of the accompanying drawings provide a step-by-step guide to the use of a camming device according to the present invention. When not in use, the device may be stored on the user's safety harness by means of the loop 56, with the arms 2, 4 in their lowered position (see left band side of FIG. 10 a) and simply be unclipped from the harness when required. In order to commence use of the device, the arms 2, 4 are rotated outwardly by bracing one of the cam ends 8 against the body of the user. When the arms 8 are fully extended (substantially horizontal), the stop member 50 locates in the groove 34 of the arms creating optimum angle and strength for bracing (Right hand side of FIG. 10 a). The device can then be inserted between two structures by simple operation of the cables 70 to pull the spring-loaded cams inwards, reducing the span of the device to less than that of the span of the crack in the rock face (FIG. 10 b). Releasing the cables allows the cams to pivot to contact the rock face, thereby bracing the device between the rock faces (FIG. 10 c). Once the device is no longer required, the top cable 56 is pulled upwardly causing a corresponding upward movement of the stop member 50 (FIG. 10 d). This results in the stop member becoming free of the groove thereby allowing rotation of the arms and removing all horizontal load from the bracing axle.

It is necessary to test the device to determine the critical failure angle when the cams will no longer be effective against the rockface. This angle is required for safety guidelines for the product.

The camming device of the present invention enables effective anchorage of a safety climbing rope between rock faces that are in excess of 100 mm apart (around 165 mm apart). This was not possible with the prior art SLCDs. It is envisaged that the device will be made in range of different sizes. Furthermore, the device is user friendly with the insertion of the device between the rockfaces and its removal therefrom being single-handed. The provision of rotatable arms linked by means of the housing results in the device having a self-righting property if the device is placed at an angle, i.e. forces during a fall would straighten the arms, thus applying more load trough the cams to the rockface.

It is to be appreciated that the camming device of the present invention may be adapted for use with structures other than rockfaces. For example, the cams could be provided with spikes 100 around their periphery to enable the camming device to penetrate ice in a similar fashion to crampons (see FIGS. 11 and 12). Ideally, a casing or rubber caps would be provided for covering the spikes when the device is not in use, thereby protecting the user from harm. 

1. A climbing aid comprising: two support arms rotatably mounted about an axis, each arm having at its free end at least one pivotally mounted cam, and at the other end a disc located on opposing sides of each arm to enable the discs to abut together when in use, wherein each disc is pivotally mounted with respect to each other and each disc further comprises a groove or slot such that when the discs and hence grooves or slots are aligned a locking means slidably mounted with respect to the discs, rests in the aligned grooves and thereby locks the arms automatically in position with respect to each other upon reaching a predetermined angle thereby preventing further rotation.
 2. A climbing aid as claimed in claim 1 wherein each arm carries two cams.
 3. A climbing aid as claimed in claim 2 wherein the cams lie parallel to each other.
 4. A climbing aid as claimed in claim 1, wherein the cams are spring-mounted and lie in the same plane as the arms.
 5. A climbing aid as claimed in claim 1 wherein the arms are locked in position when the intended lower faces of the arms are at an angle of approximately 180 degrees.
 6. A climbing aid as claimed in claim 5 wherein the maximum length of the climbing aid (i.e. with the arms in their locked position) is at least 100 mm.
 7. A climbing aid as claimed in claim 1 wherein the intended upper face of each arm is angled such that, in the locked position, the upper face lies parallel with the definitive bracing angle of the cam.
 8. A climbing aid as claimed in claim 1 wherein each arm comprises a limb having at one end a cylindrical spindle extending transversely thereto for the mounting of a cam and a circular disc at the other end, the ends of the spindle extending beyond the edges of the limb.
 9. A climbing aid as claimed in claim 8 wherein each disc is approximately half the breadth of the limb and is provided with a groove or slot in the intended upper region thereof.
 10. A climbing aid as claimed in claim 8 wherein each disc is provided with a bore through the centre thereof for receiving an axle.
 11. A climbing aid as claimed in claim 1 wherein the locking means comprises a stop member that is slidably mounted with respect to the discs.
 12. A climbing aid as claimed in claim 11 wherein the stop member is slidably located within a housing that bridges the arms of the device, the housing having two legs that lie parallel with the face of the discs and a crosspiece that lies above the top of the discs, each leg having a longitudinal slot for passage of the stop member.
 13. A climbing aid as claimed in claim 11 wherein the stop member is biased towards its lowered or locked position.
 14. A climbing aid as claimed in claim 12 wherein an axle upon which the arms are mounted extends between the legs of the housing, being secured by suitable means.
 15. A climbing aid as claimed in claim 1 wherein means is provided for affecting rotating of the cams.
 16. A climbing aid as claimed in claim 15 wherein a cable or strapping is attached to each cam to allow manual rotation of the cams.
 17. A climbing aid as claimed in claim 1 wherein the profile of the periphery of the cams is ribbed or spiked.
 18. A climbing aid as claimed in claim 1 constructed from Aerospace Grade 7075 stem alloy.
 19. A climbing aid as claimed in claim 1 wherein at least the arms or cams are provided with weight-saving holes therethrough. 